Display device

ABSTRACT

According to one embodiment, a display device includes a first transparent substrate including a first main surface, a second transparent substrate including a first end portion, a liquid crystal layer containing strip-shaped polymers and liquid crystal molecules, a third transparent substrate including a second end portion and a second main surface, a first light-emitting element and a first light guide. The first light guide includes a first surface and a second surface. A height from the first main surface to the second surface is less than a height from the first main surface to the second main surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a Continuation Application of PCT Application No.PCT/JP2019/038397, filed Sep. 27, 2019 and based upon and claiming thebenefit of priority from Japanese Patent Application No. 2018-191817,filed Oct. 10, 2018, the entire contents of all of which areincorporated herein by reference.

FIELD

Embodiments described herein relate generally to a display device.

BACKGROUND

Recently, various modes of display devices have been proposed. Forexample, such an illumination device is disclosed, that comprises alight modulating layer containing a bulk having optical anisotropy andmicro-particles in a light modulating element attached to a light guide.In another example, such a light source device is disclosed, thatcomprises an optical converter unit containing polymer dispersed liquidcrystal and converting the intensity of incident light. Further, inanother example, a display device is disclosed, in which a light sourceand a light guide are attached to a frame, which is provided on a sideof a liquid crystal panel.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a plan view showing a configuration example of a displaydevice DSP according to an embodiment.

FIG. 2 is a cross-sectional view showing a configuration example of adisplay panel PNL shown in FIG. 1.

FIG. 3 is a perspective view showing a main part of the display deviceDSP shown in FIG. 1.

FIG. 4 is an enlarged cross-sectional view showing an extending portionEx of the display device DSP shown in FIG. 3.

FIG. 5 is a cross-sectional view showing another configuration exampleof the display device DSP.

FIG. 6 is a cross-sectional view showing still another configurationexample of the display device DSP.

FIG. 7 is a cross-sectional view showing still another configurationexample of the display device DSP.

FIG. 8 is a cross-sectional view showing still another configurationexample of the display device DSP.

FIG. 9 is a cross-sectional view showing still another configurationexample of the display device DSP.

FIG. 10 is a cross-sectional view showing still another configurationexample of the display device DSP.

FIG. 11 is a cross-sectional view showing still another configurationexample of the display device DSP.

FIG. 12 is a cross-sectional view showing still another configurationexample of the display device DSP.

FIG. 13 is a plan view showing still another configuration example ofthe display device DSP.

FIG. 14 is a cross-sectional view of the display device DSP taken alongline A-B shown in FIG. 13.

FIG. 15 is a plan view showing still another configuration example ofthe display device DSP.

FIG. 16 is a cross-sectional view showing still another configurationexample of the display device DSP.

DETAILED DESCRIPTION

In general, according to one embodiment, there is provided a displaydevice comprising a first transparent substrate comprising a first mainsurface, a second transparent substrate comprising a first end portionand opposing the first main surface, a liquid crystal layer locatedbetween the first transparent substrate and the second transparentsubstrate and containing strip-shaped polymers and liquid crystalmolecules, a third transparent substrate comprising a second end portionand a second main surface on an opposite side to a surface opposing thesecond transparent substrate, and adhered to the second transparentsubstrate, a first light-emitting element opposing the first end portionand the second end portion and a first light guide overlapping the firstmain surface and located between the first and second end portions andthe first light-emitting element. The first light guide comprises afirst surface opposing the first main surface and a second surface on anopposite side to the first surface. A height from the first main surfaceto the second surface is less than a height from the first main surfaceto the second main surface.

According to another embodiment, there is provided a display devicecomprising a first transparent substrate comprising a first end portion,a first main surface and a second main surface on an opposite side tothe first main surface, a second transparent substrate comprising asecond end portion and opposing the second main surface, a liquidcrystal layer located between the first transparent substrate and thesecond transparent substrate and containing strip-shaped polymers andliquid crystal molecules, a third transparent substrate adhered to thesecond transparent substrate and comprising a third main surface, afirst light-emitting element opposing the first end portion and thesecond end portion and a first light guide overlapping the third mainsurface and located between the first and second end portions and thefirst light-emitting element. The first light guide comprises a firstsurface opposing the third main surface and a second surface on anopposite side to the first surface. A height from the third main surfaceto the second surface is less than a height from the third main surfaceto the first main surface.

According to still another embodiment, there is provided a displaydevice comprising a first transparent substrate comprising a first mainsurface, a second transparent substrate comprising a first end portionand a second main surface on an opposite side to a surface opposing thefirst transparent substrate, a liquid crystal layer located between thefirst transparent substrate and the second transparent substrate andcontaining strip-shaped polymers and liquid crystal molecules, a firstlight-emitting element opposing the first end portion and a first lightguide overlapping the first main surface and located between the firstend portion and the first light-emitting element. The first light guidecomprises a first surface opposing the first main surface and a secondsurface on an opposite side to the first surface. A height from thefirst main surface to the second surface is less than a height from thefirst main surface to the second main surface.

Embodiments will be described hereinafter with reference to theaccompanying drawings. The disclosure is a mere example, and arbitrarychange of gist which can be easily conceived by a person of ordinaryskill in the art naturally falls within the inventive scope. To moreclarify the explanations, the drawings may pictorially show width,thickness, shape and the like, of each portion as compared with anactual aspect, but they are mere examples and do not restrict theinterpretation of the invention. In the present specification anddrawings, elements like or similar to those in the already describeddrawings may be denoted by similar reference numbers and their detaileddescriptions may be arbitrarily omitted.

FIG. 1 is a plan view showing a configuration example of a displaydevice DSP according to the embodiment. For example, a first directionX, a second direction Y and a third direction Z are orthogonal to eachother, but may intersect at an angle other than ninety degrees. Thefirst direction X and the second direction Y correspond to thedirections parallel to a main surface of a substrate which constitutesthe display device DSP, and the third direction Z corresponds to thethickness direction of the display device DSP. In the followingexplanations, a direction from the first substrate SUB1 toward thesecond substrate SUB2 is referred to as upward (or merely above), and adirection from the second substrate SUB2 toward the first substrate SUB1is referred to as downward (or merely below). With such expressions as“a second member above a first member” and “a second member below afirst member”, the second member may be in contact with the first memberor may be remote from the first member. In addition, an observationposition at which the display device DSP is observed is assumed to belocated on the tip side of the arrow indicating the third direction Z,and viewing from the observation position toward an X-Y plane defined bythe first direction X and the second direction Y is called a plan view.

In the embodiment, a liquid crystal display device employing polymerdispersed liquid crystal applied thereto will be explained as an exampleof the display device DSP. The display device DSP comprises a displaypanel PNL, an IC chip 1 and a wiring substrate 2.

The display panel PNL comprises a first substrate SUB1, a secondsubstrate SUB2, a liquid crystal layer LC and a sealant SE. The firstsubstrate SUB1 and the second substrate SUB2 are each formed into a flatplate parallel to the X-Y plane. The first substrate SUB1 and the secondsubstrate SUB2 overlap in plan view. The first substrate SUB1 and thesecond substrate SUB2 are adhered to each other by a sealant SE. Theliquid crystal layer LC is held between the first substrate SUB1 and thesecond substrate SUB2, and sealed by the sealant SE. In FIG. 1, theliquid crystal layer LC and the sealant SE are indicated by differenthatch lines.

As shown schematically and enlarged in FIG. 1, the liquid crystal layerLC comprises a polymer dispersed liquid crystal which contains polymers31 and liquid crystal molecules 32. For example, the polymer 31 is aliquid crystal polymer. The polymers 31 extend into a strip shape. Anextending direction D1 of the polymers 31 is parallel to the firstdirection X. The liquid crystal molecules 32 are dispersed in gapsbetween the polymers 31 and aligned such that their longitudinal axesextend in the first direction X. The polymers 31 and the liquid crystalmolecules 32 each have optical anisotropy or refractive anisotropy. Theresponse performance of the polymers 31 to the electric field is lowerthan the response performance of the liquid crystal molecules 32 to theelectric field.

For example, the orientation of alignment of the polymers 31 is hardlyvaried regardless of the presence or absence of an electric field. Onthe other hand, the orientation of alignment of the liquid crystalmolecules 32 is varied in accordance with the electric field in a statewhere a voltage higher than the threshold value is applied to the liquidcrystal layer LC. While voltage is not applied to the liquid crystallayer LC, the optical axes of the polymers 31 and the liquid crystalmolecules 32 are parallel to each other and light entering the liquidcrystal layer LC is transmitted without being substantially scattered inthe liquid crystal layer LC (a transparent state). While voltage isapplied to the liquid crystal layer LC, the optical axes of the polymers31 and the liquid crystal molecules 32 intersect each other, and lightentering the liquid crystal layer LC is scattered in the liquid crystallayer LC (a scattering state).

The display panel PNL includes a display part DA which displays imagesand a frame-shaped non-display part NDA surrounding the display part DA.The display part DA comprises pixels PX arranged in a matrix form in thefirst direction X and the second direction Y. The sealant SE is locatedin the non-display part NDA.

As enlargedly shown in FIG. 1, each of the pixels PX comprises aswitching element SW, a pixel electrode PE, a common electrode CE, aliquid crystal layer LC, and the like. The switching element SW isformed of, for example, a thin-film transistor (TFT) and is electricallyconnected to the scanning line G and the signal line S. The scanningline G is electrically connected to the switching element SW in each ofpixels PX which are arranged in the first direction X. The signal line Sis electrically connected to the switching element SW in each of pixelsPX which are arranged in the second direction Y. The pixel electrode PEis electrically connected to the switching element SW. Each of the pixelelectrodes PE opposes the common electrode CE, and drives the liquidcrystal layer LC (particularly, the liquid crystal molecules 32) by anelectric field generated between the pixel electrode PE and the commonelectrode CE. A capacitor CS is formed, for example, between anelectrode having the same potential as that of the common electrode CEand an electrode having the same potential as that of the pixelelectrode PE.

The first substrate SUB1 includes end portions E11 and E12 extending inthe first direction X, and end portions E13 and E14 extending in thesecond direction Y. The second substrate SUB2 includes end portions E21and E22 extending in the first direction X, and end portions E23 and E24extending in the second direction Y. In the example illustrated, the endportion E11 and the end portion E22 overlap each other, the end portionsE13 and E23 overlap each other, and the end portions E14 and E24 overlapeach other, in plan view. The end portion E21 is located between the endportion E11 and the display part DA in plan view. The first substrateSUB1 includes an extending portion Ex between the end portions E11 andE21.

The wiring substrate 2 is electrically connected to the extendingportion Ex. The wiring substrate 2 is a flexible printed circuit boardwhich can be bent. The IC chip 1 is electrically connected to the wiringsubstrate 2. The IC chip 1 contains, for example, a display driver DDincorporated therein, which outputs signals necessary to display images.Note that the IC chip 1 may be electrically connected to the extendingportion Ex. In some cases, the IC chip 1 and the wiring substrate 2 readsignals from the display panel PNL, but it mainly functions as a signalsource supplying signals to the display panel PNL.

FIG. 2 is a cross-sectional view showing a configuration example of thedisplay panel PNL shown in FIG. 1. The first substrate SUB1 comprises atransparent substrate 10, an insulating film 11, an insulating film 12,a capacitor electrode 13, switching elements SW, pixel electrodes PE andan alignment film AL1. The first substrate SUB1 further comprisesscanning lines G and signal lines S shown in FIG. 1. The transparentsubstrate 10 comprises a main surface (a lower surface) 10A and anothermain surface (an upper surface) 10B on an opposite side to the mainsurface 10A. The switching elements SW are disposed on the main surface10B. The insulating film 11 covers the switching elements SW. Thecapacitor electrode 13 is located between the insulating film 11 and theinsulating film 12. The pixel electrodes PE are disposed on theinsulating film 12 such that each electrode is for the respective pixelPX. The pixel electrodes PE are electrically connected to the switchingelements SW, respectively, via respective opening portions OP of thecapacitor electrode 13. The pixel electrodes PE overlap the capacitorelectrode 13 via the insulating film 12 and they each form a capacitorCS of the respective pixel PX. The alignment film AL1 covers the pixelelectrodes PE.

The second substrate SUB2 comprises a transparent substrate 20,light-shielding layers BM, a common electrode CE and an alignment filmAL2. The transparent substrate 20 comprises a main surface (a lowersurface) 20A and another main surface (an upper surface) 20B on anopposite side of the main surface 20A. The main surface 20A of thetransparent substrate 20 opposes the main surface 10B of the transparentsubstrate 10. The light-shielding layer BM and the common electrode CEare disposed on the main surface 20A. The light-shielding layers BM arelocated, for example, directly above the switching elements SW,respectively and directly above the scanning lines G and the signallines S, respectively. The common electrode CE are disposed over aplurality of pixels PX and directly covers the light-shielding layersBM. The common electrode CE is electrically connected to the capacitorelectrodes 13 and at the same potential as that of the capacitorelectrodes 13. The alignment film AL2 covers the common electrode CE.The liquid crystal layer LC is located between the main surface 10B andthe main surface 20A, and is in contact with the alignment films AL1 andAL2. In the first substrate SUB1, the insulating film 11, the insulatingfilm 12, the capacitor electrodes 13, the switching elements SW, thepixel electrodes PE and the alignment film AL1 are located between themain surface 10B and the liquid crystal layer LC. In the secondsubstrate SUB2, the light-shielding layers BM, the common electrode CEand the alignment film AL2 are located between the main surface 20A andthe liquid crystal layer LC.

The transparent substrates 10 and 20 are insulating substrates such asof glass or plastic. The main surfaces 10A and 10B and the main surfaces20A and 20B are surfaces substantially parallel to the X-Y plane. Theinsulating film 11 is formed from a transparent insulation material suchas of silicon oxide, silicon nitride, silicon oxynitride, acryl resin orthe like. For example, the insulating film 11 includes an inorganicinsulating film and an organic insulating film. The insulating film 12is an inorganic insulating film such as of silicon nitride or the like.The capacitor electrodes 13, the pixel electrodes PE and the commonelectrode CE are transparent electrodes made of a transparent conductivematerial such as indium tin oxide (ITO), indium zinc oxide (IZO) or thelike. For example, the light-shielding layers BM are conductive layershaving a resistance lower than that of the common electrode CE. Forexample, the light-shielding layers BM are formed of a non-transparentmetal material such as molybdenum, aluminum, tungsten, titanium, silveror the like. The alignment films AL1 and AL2 are horizontal alignmentfilms substantially parallel to the X-Y plane, which have an alignmentrestriction force. For example, the alignment films AL1 and AL2 aresubjected to an alignment treatment in the first direction X. Note thatthe alignment treatment may be a rubbing treatment or an opticalalignment treatment.

FIG. 3 is a perspective diagram showing a main part of the displaydevice DSP shown in FIG. 1. The display device DSP comprises atransparent substrate 30 and light source unit LU1 in addition to thedisplay panel PNL. The light source unit LU1 is located in the extendingportion Ex. The transparent substrate 10, the transparent substrate 20and the transparent substrate 30 are arranged in this order in the thirddirection Z.

The transparent substrate 30 is formed of, for example, transparentglass or a transparent resin such as polymethyl methacrylate (PMMA),polycarbonate (PC), or the like. The transparent substrate 30 comprisesa main surface (a lower surface) 30A, another main surface (a uppersurface) 30B on an opposite side to the main surface 30A, end portionsE31 and E32 extending in the first direction X and end portions E33 andE34 extending in the second direction Y. The main surface 30A opposesthe main surface 20B of the transparent substrate 20. In the exampleillustrated, the end portion E31 overlaps the end portion E21, and theend portion E32 overlaps the end portion E22. Note that the end portionE32 may not necessarily overlap the end portion E22.

The light source units LU1 each comprise a plurality of light-emittingelements LD1, a light guide LG1 and a wiring substrate F1. Thelight-emitting elements LD1 are arranged in the extending direction D1of polymer 31 shown in FIG. 1 with intervals respectively therebetween.The light-emitting elements LD1 are connected to the wiring substrateF1. The light-emitting elements LD1 are located between the transparentsubstrate 10 and the wiring substrate F1. The light-emitting elementsLD1 oppose the end portion E21 of the transparent substrate 20 and theend portion E31 of the transparent substrate 30. The light-emittingelements LD1 are, for example, light-emitting diodes. Light irradiatedfrom the light-emitting elements LD1 proceeds in a direction of an arrowindicating the second direction Y.

The light guide LG1 is formed into a rectangular parallelepiped shapeelongated along the first direction X. The light guide LG1 is locatedbetween the transparent substrates 20 and 30 and the light-emittingelements LD1. The light guide LG1 comprises a surface (a lower surface)1A, another surface (an upper surface) 1B on an opposite side to thesurface 1A, another surface 1C and another surface 1D on an oppositeside to the surface 1C. The surface 1A opposes the transparent substrate10, the surface 1B opposes the wiring substrate F1, the surface 1Copposes the light-emitting elements LD1, and the surface 1D opposes thetransparent substrates 20 and 30. For example, each of the surfaces 1Aand 1B is a flat surface parallel to the X-Y plane defined by the firstdirection X and the second direction Y. In other words, the surfaces 1Aand 1B are parallel to each other. Each of the surfaces 1C and 1D is aflat surface parallel to the X-Z plane defined by the first direction Xand the third direction Z. Note that the surfaces 1C and 1D may beirregular surfaces with projections and recesses or the surfaces 1C and1D may not necessarily parallel to each other.

FIG. 4 is an enlarged cross-sectional view showing the extending portionEx and its surroundings of the display device DSP shown in FIG. 3. Notethat, as to the display panel PNL, only a main part is illustrated. Thedisplay device DSP further comprises an adhesive layer 40, anotheradhesive layer 50 and a transparent adhesive layer AD.

The first substrate SUB1 further comprises an insulating film 14, aninsulating film 15 and metal wiring line 16. The insulating film 14 islocated on the main surface 10B. The metal wiring line 16 is located onthe insulating film 14, and is covered by the insulating film 15. Theinsulating film 15 is equivalent to the insulating film 11 or 12 shownin FIG. 2. The metal wiring line 16 is formed of, for example, the samematerial as that of the scanning lines G or the signal lines S.

The light-emitting elements LD1 each comprise a light-emitting portionEM1 opposing the surface 1C of the light guide LG1. The light-emittingportion EM1 is spaced apart from the surface 1C. The light-emittingportion EM1 comprises a red light-emitting unit, a green light-emittingunit and a blue light-emitting unit. These color light-emitting portionsare provided in the light-emitting portion EM1, but these may notnecessarily be located on the same straight line in the first directionX. In other words, these color light-emitting units may be provided atpositions different from each other in height from the first substrateSUB1 in the third direction Z. The light-emitting portion EM1 is locatedbetween the surface 1A and the surface 1B of the first light guide LG1in the third direction Z.

The adhesive layer 40 adheres the wiring substrate F1 and the lightguide LG1 together. In the example illustrated, the adhesive layer 40 islocated between the surface 1B and the wiring substrate F1. The adhesivelayer 50 adheres the light source units LU1 and the first substrate SUB1together. In the example illustrated, the adhesive layer 50 is locatedbetween the surface 1A and the main surface 10B, and adheres the firstlight guide LG1 and the insulating film 15 together. Thus, the lightsource unit LU1 is fixed to the first substrate SUB1.

The adhesive layer 40 comprises a reflective member M1 and the adhesivelayer 50 comprises a reflective member M2. The reflective member M1 islocated between the wiring substrate F1 and the surface 1B. Thereflective member M2 is located between the insulating film 15 and thesurface 1A. The adhesive layers 40 and 50 each are a stacked layer bodyin which, for example, an adhesive material, a reflective member and anadhesive material are stacked in this order, and are, for example,double-sided tapes. The reflective members M1 and the M2 are each formedof, for example, a highly reflective metallic material such as aluminum,molybdenum, titanium, silver or the like. Note that the reflectivemembers M1 and the M2 may be light-shielding members as well.

The transparent adhesive layer AD is located between the main surface20B and the main surface 30A. The transparent adhesive layer AD is incontact with each of the main surface 20B and the main surface 30Asubstantially in its entirety, and adheres the transparent substrate 20and the transparent substrate 30 together.

Here, the positions of the light guide LG1, the transparent substrate10, the transparent substrate 20 and the transparent substrate 30 inrelation to each other will be focused.

The transparent substrate 10 has a thickness T1, the transparentsubstrate 20 has a thickness T2, the transparent substrate 30 has athickness T3, and the light guide LG1 has a thickness T10. Note that theterm “thickness” in this specification is equivalent to the length inthe third direction Z. The thickness T1 is equivalent to a distance fromthe main surface 10A to the main surface 10B, the thickness T2 isequivalent to a distance from the main surface 20A to the main surface20B, the thickness T3 is equivalent to a distance from the main surface30A to the main surface 30B, and the thickness T10 is equivalent to adistance from the surface 1A to the surface 1B. In the exampleillustrated, the thickness T1 is similar to the thickness T2, and thethickness T3 is similar to the thicknesses T1 and T2. Note that thethickness T3 may be different from the thicknesses T1 and T2. Thethickness T10 is greater than any one of the thickness T1 to thethickness T3. A height H1 taken from the main surface 10B to the surface1B is less than a height H2 taken from the main surface 10B to the mainsurface 30B in the third direction Z. Further, a height H3 taken fromthe main surface 10B to the surface 1A is greater than a height H4 takenfrom the main surface 10B to the main surface 20A in the third directionZ. In other words, the surface 1D is located between the main surface20A and the main surface 30B along the third direction Z. The lightemitted from the light-emitting portion EM1 enters the light guide LG1from the surface 1C and proceeds in the light guide LG1 while beingreflected on the surface 1A and the surface 1B. The light transmitted inthe light guide LG1 is emitted from the surface 1D and enters thetransparent substrate 20 and the transparent substrate 30 from the endportion E21 and the end portion E31, respectively.

According to this embodiment, the light guide LG1 comprises the surface1D in a position lower than the main surface 30B in the third directionZ. With this structure, most of the light transmitted in the light guideLG1 is guided to the end portion E21 and the end portion E31, to be ableto contribute to display on the display panel PNL, thus suppressing thedegradation of the light-entering efficiency.

Further, the reflective member M1 is located between the surface 1B andthe wiring substrate F1. Of the light transmitted in the light guideLG1, a light having passed the surface 1B is reflected by the reflectivemember M1 and does not reach the wiring substrate F1. Thus, it ispossible to inhibit the light proceeding in the light guide LG1 frombeing colored by the wiring substrate F1. On the other hand, thereflective member M2 is located between the surface 1A and the metalwiring lines 16. Of the light transmitted in the light guide LG1, theportion having passed the surface 1A is reflected by the reflectivemember M2 and does not reach the metal wiring lines 16. Thus, it ispossible to inhibit the light proceeding in the light guide LG1 frombeing undesirably scattered by the metal wiring lines 16. Therefore,deterioration in display quality can be suppressed.

Furthermore, the wiring substrate F1 connected to the light-emittingelements LD1 is adhered to the light guide LG1 via the adhesive layer40, and the light guide LG1 is adhered to the insulating film 15 via theadhesive layer 50. With this structure, the optical unit LU1 can befixed to the first substrate SUB1 without providing a frame to fix theoptical unit LU1, thereby making it possible to lighten the displaydevice DSP in weight.

In the example shown in FIG. 4, the transparent substrates 10 to 30 areequivalent to the first transparent substrate to the third transparentsubstrate, respectively, the light-emitting element LD1 is equivalent tothe first light-emitting element, the light guide LG1 is equivalent tothe first light guide, the wiring substrate F1 is equivalent to thefirst wiring substrate, the adhesive layer 40 is equivalent to the firstadhesive layer, the adhesive layer 50 is equivalent to the secondadhesive layer, the main surface 10B is equivalent to the first mainsurface, the main surface 30B is equivalent to the second main surface,the end portion E21 is equivalent to the first end portion, the endportion E31 is equivalent to the second end portion, the surface 1A isequivalent to the first surface, and the surface 1B is equivalent to thesecond surface.

FIG. 5 is a cross-sectional view showing another configuration exampleof the display device DSP. The configuration example shown in FIG. 5 isdifferent from that of FIG. 4 in that a length L1 taken from the surface1C to the surface 1D in the second direction Y is greater in thisexample. The length L1 should preferably be, for example, 20 mm or more.The length L1 is greater than a length L2 taken from the end portion E11to the end portion E21. The end portion E11 is located between thesurface 1C and the end portions E21 and E31 in the second direction Y.The surface 1A is in contact with an air layer in an area NA which isnot in contact with the adhesive layer 50. With this structure, of thelight proceeding in the light guide LG1, a light proceeding to the areaNA is reflected by an interface between the air layer and itself.

In such a configuration example as well, an advantageous effect similarto that of shown in FIG. 4 can be obtained. In addition, the length L1is 20 mm or more. Thus, the distance from the light-emitting portion EM1to the end portions E21 E31 is long, and therefore the light emittedfrom the light-emitting portion EM1 is mixed while the light proceedingin the light guide LG1. In this manner, degradation in display quality,which may be caused by the non-uniformity of the illumination light canbe suppressed.

In the example shown in FIG. 5, the surface 1D is equivalent to thethird surface, and the surface 1C is equivalent to the fourth surface.

FIG. 6 is a cross-sectional view showing still another configurationexample of the display device DSP. The configuration example shown inFIG. 6 is different from that of FIG. 4 in that the wiring substrate F1is located between the light guide LG1 and the transparent substrate 10.The adhesive layer 40 is located between the surface 1A and the wiringsubstrate F1. The adhesive layer 40 comprises a reflective member M1.The adhesive layer 50 is located between the insulating film 15 and thewiring substrate F1. In the example illustrated, the adhesive layer 50does not comprise a reflective member. The light guide LG1 is in contactwith the air layer in the surface 1B.

In such a configuration example as well, an advantageous effect similarto that of shown in FIG. 4 can be obtained. In addition, in thisexample, the surface 1B is in contact with the air layer, light is notabsorbed by other members in the surface 1B. Therefore, it is possibleto suppress degradation of the light-entering efficiency of the lightemitted from the light-emitting portion EM1 to the transparentsubstrates 20 and 30.

FIG. 7 is a cross-sectional view showing still another configurationexample of the display device DSP. The configuration example shown inFIG. 7 is different from that of FIG. 4 in that the light source unitLU1 overlaps the main surface 30A. The end portion E32 does not overlapthe end portion E12 and the end portion E22. The light-emitting elementLD1 opposes the end portions E12 and E22. The wiring substrate F1opposes the surface 1B. The adhesive layer 40 is located between thesurface 1B and the wiring substrate F1, and adheres the wiring substrateF1 and the light guide LG1 together. The adhesive layer 50 is locatedbetween the surface 1A and the main surface 30A, and adheres the lightguide LG1 and the transparent substrate 30 together. The reflectivemember M2 is located between the surface 1A and the main surface 30A.The light guide LG1 overlaps the main surface 30A and is located betweenthe end portions E12 and E22 and the light-emitting element LD1. Aheight H5 taken from the main surface 30A to the surface 1B is less thana height H6 taken from the main surface 30A to the main surface 10A inthe third direction Z. A height H7 taken from the main surface 30A tothe surface 1A is greater than a height H8 taken from the main surface30A to the main surface 20B in the third direction Z. In other words,the surface 1D is located between the main surface 20B and the mainsurface 10A in the third direction Z.

In such a configuration example as well, an advantageous effect similarto that of shown in FIG. 4 can be obtained.

In the example shown in FIG. 7, the end portion E12 is equivalent to thefirst end portion, the end portion E22 is equivalent to the second endportion, the main surface 10A is equivalent to the first main surface,the main surface 10B is equivalent to the second main surface, and themain surface 30A is equivalent to the third main surface.

FIG. 8 is a cross-sectional view showing still another configurationexample of the display device DSP. The configuration example shown inFIG. 8 is different from that of FIG. 6 in that the light source unitLU1 overlaps the main surface 30A. The wiring substrate F1 is locatedbetween the surface 1A of the light guide LG1 and the main surface 30Aof the transparent substrate 30. The adhesive layer 40 is locatedbetween the surface 1A and the wiring substrate F1, and adheres thelight guide LG1 and the wiring substrate F1 together. The adhesive layer50 is located between the main surface 30A and the wiring substrate F1,and adheres the wiring substrate F1 and the transparent substrate 30together.

In such a configuration example as well, an advantageous effect similarto that of shown in FIG. 6 can be obtained.

FIG. 9 is a cross-sectional view showing still another configurationexample of the display device DSP. The configuration example shown inFIG. 9 is different from that of FIG. 4 in that the display device DSPcomprises a light source unit LU2. The light source unit LU2 has astructure similar to that of the light source unit LU1 shown in FIG. 7.The light source unit LU2 comprises a plurality of light-emittingelements LD2, a light guide LG2 and a wiring substrate F2.

The light-emitting elements LD2 oppose the end portion E11 of thetransparent substrate 10 and the end portion E22 of the transparentsubstrate 20. Light emitted from light-emitting portions EM2 of therespective light-emitting elements LD2 proceeds reverse to the directionindicated by the arrow representing the second direction Y. Thelight-emitting elements LD2 are connected to the wiring substrate F2. Anadhesive layer 60 adheres the wiring substrate F2 and the light guideLG2 together. The adhesive layer 60 contains a reflective member M3. Anadhesive layer 70 adheres the light guide LG2 and the transparentsubstrate 30 together. The adhesive layer 70 contains a reflectivemember M4. The light guide LG2 comprises a surface (an upper surface)2A, another surface (lower surface) 2B on an opposite side to thesurface 2A, a surface 2C and a surface 2D on an opposite side to thesurface 2C. The surface 2A opposes the transparent substrate 30, thesurface 2B opposes the wiring substrate F2, the surface 2C opposes thelight-emitting elements LD2, and the surface 2D opposes the transparentsubstrate 10 and the transparent substrate 20. The surface 2A andsurface 2B are parallel to each other. A height H5 taken from the mainsurface 30A to the surface 2B is less than a height H6 taken from themain surface 30A to the main surface 10A in the third direction Z.

In the example shown in FIG. 9, the light-emitting elements LD2 areequivalent to the second light-emitting element, the light guide LG2 isequivalent to the second light guide, the wiring substrate F2 isequivalent to the second wiring substrate, the adhesive layer 60 isequivalent to the third adhesive layer, the adhesive layer 70 isequivalent to the fourth adhesive layer, the main surface 10A isequivalent to the third main surface, the main surface 30A is equivalentto the fourth main surface, the surface 2A is equivalent to fifthsurface, the surface 2B is equivalent to the sixth surface, the endportion E12 is equivalent to the third end portion, and the end portionE22 is equivalent to the fourth end portion.

FIG. 10 is a cross-sectional view showing still another configurationexample of the display device DSP. The configuration example shown inFIG. 10 is different from that of FIG. 9 in that the wiring substrate F2is located between the light guide LG2 and the transparent substrate 30.The light source unit LU2 has a structure similar to that of the lightsource unit LU1 shown in FIG. 8. The adhesive layer 60 contains areflective member M3. The adhesive layer 70 adheres the wiring substrateF2 and the transparent substrate 30 together. In the exampleillustrated, the adhesive layer 70 is located between the main surface30A and the wiring substrate F2. The surface 2B of the light guide LG2is in contact with the air layer.

FIG. 11 is a cross-sectional view showing still another configurationexample of the display device DSP. The configuration example shown inFIG. 11 is different from that of FIG. 9 in that the light source unitLU1 has a structure similar to that of the light source unit LU1 shownin FIG. 6.

FIG. 12 is a cross-sectional view showing still another configurationexample of the display device DSP. The configuration example shown inFIG. 12 is different from that of FIG. 11 in that the light source unitLU2 has a structure similar to that of the light source unit LU1 shownin FIG. 8.

In the configuration examples shown in FIGS. 9 to 12 as well, anadvantageous effect similar to that of shown in FIG. 6 can be obtained.Further, in these examples, the light emitted from the light-emittingportion EM2 enters from the end portion E12 and the end portion E22, andtherefore the amount of light entering the display panel PNL increases.Thus, even if the display panel PNL is enlarged in size and accordinglythe display part DA is expanded, degradation of the brightness can beinhibited over the entire display part DA, and degradation in displayquality can be inhibited.

FIG. 13 is a plan view showing still another configuration example ofthe display device DSP. The configuration example shown in FIG. 13 isdifferent from that of FIG. 9 in that the transparent substrate 30extends along the first direction X, the light source unit LU1 islocated between the end portion E23 and the end portion E33, and thelight source unit LU2 is located between the end portion E24 and the endportion E34. In the example illustrated, the extending direction D1 ofthe polymers 31 is parallel to the second direction Y. The end portionE33 does not overlap the end portion E13 and the end portion E23. Theend portion E34 does not overlaps the end portion E14 and the endportion E24.

The light-emitting elements LD1 are arranged in the extending directionD1 of the polymer 31 with intervals respectively therebetween. The lightguide LG1 is located between the light-emitting elements LD1 and the endportion E23, and extends in the second direction Y. The light-emittingelements LD2 are arranged in the extending direction D1 of the polymers31 with intervals respectively therebetween. The light guide LG2 islocated between the light-emitting elements LD2 and the end portion E24,and extends in the second direction Y.

FIG. 14 is a cross-sectional view of the display device DSP taken alongline A-B shown in FIG. 13. In the example illustrated, the light sourceunits LU1 and LU2 have a structure similar to that of the light sourceunit LU1 shown in FIG. 7, but they may have a structure similar to thatof the light source unit LU1 shown in FIG. 8. The light source unit LU1and the light source unit LU2 overlap the main surface 30A.

The light-emitting elements LD1 oppose the end portion E13 of thetransparent substrate 10 and the end portion E23 of the transparentsubstrate 20. Light emitted from the light-emitting portions EM1 of thelight-emitting elements LD1 proceeds towards a direction indicated bythe arrow representing the first direction X. The surface 1D of thelight guide LG1 opposes the end portion E13 and the end portion E23. Thelight emitted from the light-emitting portions EM1 proceeds in the lightguide LG1 and enters the transparent substrate 10 and the transparentsubstrate 20 from the end portion E13 and the end portion E23,respectively.

The light-emitting elements LD2 oppose the end portion E14 of thetransparent substrate 10 and the end portion E24 of the transparentsubstrate 20. The light emitted from the light-emitting portions EM2 ofthe light-emitting elements LD2 proceed reverse to the directionindicated by the arrow representing the first direction X. The surface2D of the light guide LG2 opposes the end portion E14 and the endportion E24. The light emitted from the light-emitting portions EM2proceeds in the light guide LG2 and enters the transparent substrate 10and the transparent substrate 20 from the end portion E14 and the endportion E24, respectively.

In such a configuration example as well, an advantageous effect similarto that of shown in FIG. 9 can be obtained.

FIG. 15 is a plan view showing still another configuration example ofthe display device DSP. The configuration example shown in FIG. 15 isdifferent from that of FIG. 9 in that the transparent substrate 30expands in each of the first direction X and the second direction Y, andthe display device DSP comprises light source units LU3 and LU4. In theexample illustrated, the extending direction D1 of the polymers 31intersects each of the first direction X and the second direction Y. Theend portion E33 does not overlap the end portion E13 and the end portionE23. The end portion E34 does not overlap the end portion E14 and theend portion E24. The light source units LU3 and LU4 have a structuresimilar to that of the light source units LU1 and LU2 shown in FIG. 13.

In such a configuration example as well, an advantageous effect similarto that of shown in FIG. 9 can be obtained. Further, in this example,the light emitted from the light-emitting elements LD3 enters from theend portion E13 and the end portion E23, and the light emitted from thelight-emitting elements LD4 enters from the end portion E14 and the endportion E24, and therefore the amount of light entering the displaypanel PNL further increases.

FIG. 16 is a cross-sectional view showing still another configurationexample of the display device DSP. The configuration example shown inFIG. 16 is different from that of FIG. 4 in that the transparentsubstrate 30 is not provided, and the transparent substrate 20 has athickness T20. The thickness T20 is equivalent to a distance taken fromthe main surface 20A to the main surface 20B. In the exampleillustrated, the thickness T20 is greater than each of the thickness T10and the thickness T1. A height H1 taken from the main surface 10B to thesurface 1B is less than a height H9 taken from the main surface 10B tothe main surface 20B in the third direction Z. In other words, thesurface 1D is located between the main surface 20A and the main surface20B in the third direction Z. Light emitted from the light-emittingportions EM1 proceeds in the light guide LG1, and is emitted from thesurface 1D. Then, the light enters the transparent substrate 20 from theend portion E21. The light source unit LU1 has a structure similar tothat of the light source unit LU1 shown in FIG. 4, but it may have astructure similar to that of light source unit LU1 shown in each ofFIGS. 5 and 6.

In such a configuration example as well, an advantageous effect similarto that of shown in FIG. 4 can be obtained. Incidentally, in the casewhere the light emitted from the light-emitting element LD1 proceeds inthe light guide LG1 and then enters an adhered member, if the endportion opposing the surface 1D of each member is displaced due to analignment error between members, degradation of the light-enteringefficiency from the light-emitting element LD1 to the display panel PNLmay be caused. With regard to this point, according to the configurationexample shown in FIG. 16, the light emitted from the light-emittingelement LD1 proceeds in the light guide LG1 and enters a singletransparent substrate 20, and therefore it is possible to inhibitdegradation of the light-entering efficiency from the light-emittingelement LD1 to the display panel PNL.

In the example shown in FIG. 16, the main surface 20B is equivalent tothe second main surface.

As explained above, according to the present embodiments, a displaydevice which can suppress the deterioration in display quality can beprovided.

While certain embodiments have been described, these embodiments havebeen presented by way of example only, and are not intended to limit thescope of the inventions. Indeed, the novel embodiments described hereinmay be embodied in a variety of other forms; furthermore, variousomissions, substitutions and changes in the form of the embodimentsdescribed herein may be made without departing from the spirit of theinventions. The accompanying claims and their equivalents are intendedto cover such forms or modifications as would fall within the scope andspirit of the inventions.

What is claimed is:
 1. A display device comprising: a first transparentsubstrate comprising a first main surface; a second transparentsubstrate comprising a first end portion and opposing the first mainsurface; a liquid crystal layer located between the first transparentsubstrate and the second transparent substrate and containingstrip-shaped polymers and liquid crystal molecules; a third transparentsubstrate comprising a second end portion and a second main surface onan opposite side to a surface opposing the second transparent substrate,and adhered to the second transparent substrate; a first light-emittingelement opposing the first end portion and the second end portion; and afirst light guide overlapping the first main surface and located betweenthe first and second end portions and the first light-emitting element,the first light guide comprising a first surface opposing the first mainsurface and a second surface on an opposite side to the first surface, aheight from the first main surface to the second surface being less thana height from the first main surface to the second main surface.
 2. Thedevice of claim 1, wherein the first surface and the second surface areparallel to each other.
 3. The device of claim 2, further comprising: afirst wiring substrate connected to the first light-emitting element andopposing the second surface; a first adhesive layer adhering the firstwiring substrate and the first light guide together; an insulating filmlocated between the first main surface and the first light guide; and asecond adhesive layer adhering the insulating film and the first lightguide together, wherein the first adhesive layer and the second adhesivelayer each comprise a reflective member.
 4. The device of claim 3,wherein the first light guide comprises a third surface opposing thefirst end portion and the second end portion, and a fourth surface on anopposite side to the third surface and opposing the first light-emittingelement, and a distance between the third surface and the fourth surfaceis 20 mm or more.
 5. The device of claim 2, further comprising: a firstwiring substrate connected to the first light-emitting element andlocated between the first light guide and the first main surface; aninsulating film located between the first main surface and the firstwiring substrate; a first adhesive layer adhering the first wiringsubstrate and the first light guide together; and a second adhesivelayer adhering the first wiring substrate and the insulating filmtogether, wherein the first adhesive layer comprising a reflectivemember, and the second surface is in contact with an air layer.
 6. Thedevice of claim 2, wherein the first transparent substrate comprises athird main surface on an opposite side to the first main surface, and athird end portion, the second transparent substrate comprises a fourthend portion on an opposite side to the first end portion, and the thirdtransparent substrate comprises a fourth main surface on an oppositeside to the second main surface, the device further comprises: a secondlight-emitting element opposing the third end portion and the fourth endportion; and a second light guide overlapping the fourth main surfaceand located between the third and fourth end portions and the secondlight-emitting element, the second light guide comprises a fifth surfaceopposing the fourth main surface and a sixth surface on an opposite sideto the fifth surface, and a height from the fourth main surface to thesixth surface is less than a height from the fourth main surface to thethird main surface.
 7. The device of claim 1, wherein the firsttransparent substrate comprises a third main surface on an opposite sideto the first main surface, and a third end portion, the secondtransparent substrate comprises a fourth end portion on an opposite sideto the first end portion, and the third transparent substrate comprisesa fourth main surface on an opposite side to the second main surface,the device further comprises: a second light-emitting element opposingthe third end portion and the fourth end portion; and a second lightguide overlapping the fourth main surface and located between the thirdand fourth end portions and the second light-emitting element, thesecond light guide comprises a fifth surface opposing the fourth mainsurface and a sixth surface on an opposite side to the fifth surface,and a height from the fourth main surface to the sixth surface is lessthan a height from the fourth main surface to the third main surface. 8.The device of claim 7, wherein the fifth surface and the sixth surfaceare parallel to each other.
 9. The device of claim 8, furthercomprising: a second wiring substrate connected to the secondlight-emitting element and opposing the sixth surface; a third adhesivelayer adhering the second wiring substrate and the second light guidetogether; and a fourth adhesive layer adhering the second light guideand the third transparent substrate together, wherein the third adhesivelayer and the fourth adhesive layer each comprise a reflective member.10. The device of claim 8, further comprising: a second wiring substrateconnected to the second light-emitting element and located between thesecond light guide and the fourth main surface; a third adhesive layeradhering the second wiring substrate and the second light guidetogether; and the fourth adhesive layer adhering the second wiringsubstrate and the third transparent substrate together, wherein thethird adhesive layer comprises a reflective member, and the sixthsurface is in contact with an air layer.
 11. The device of claim 1,further comprising: a first substrate comprising the first transparentsubstrate; a second substrate comprising the second transparentsubstrate; and a light source unit overlapping the first substrate,wherein the light source unit comprises: the first light-emittingelement; the first light guide; a first wiring substrate connected tothe first light-emitting element; a first adhesive layer adhering thefirst wiring substrate and the first light guide together; and a secondadhesive layer adhering the first substrate and the first light guidetogether.
 12. A display device comprising: a first transparent substratecomprising a first end portion, a first main surface and a second mainsurface on an opposite side to the first main surface; a secondtransparent substrate comprising a second end portion and opposing thesecond main surface; a liquid crystal layer located between the firsttransparent substrate and the second transparent substrate andcontaining strip-shaped polymers and liquid crystal molecules; a thirdtransparent substrate adhered to the second transparent substrate andcomprising a third main surface; a first light-emitting element opposingthe first end portion and the second end portion; and a first lightguide overlapping the third main surface and located between the firstand second end portions and the first light-emitting element, the firstlight guide comprising a first surface opposing the third main surfaceand a second surface on an opposite side to the first surface, a heightfrom the third main surface to the second surface being less than aheight from the third main surface to the first main surface.
 13. Thedevice of claim 12, further comprising: a first wiring substrateconnected to the first light-emitting element and opposing the secondsurface; a first adhesive layer adhering the first wiring substrate andthe first light guide together; and a second adhesive layer adhering thethird transparent substrate and the first light guide together, whereinthe first adhesive layer and the second adhesive layer each comprise areflective member.
 14. The device of claim 12, further comprising: afirst wiring substrate connected to the first light-emitting element andlocated between the first surface and the third main surface; a firstadhesive layer adhering the first wiring substrate and the first lightguide together; and a second adhesive layer adhering the thirdtransparent substrate and the first wiring substrate together, whereinthe first adhesive layer comprises a reflective member, and the secondsurface is in contact with an air layer.
 15. A display devicecomprising: a first transparent substrate comprising a first mainsurface; a second transparent substrate comprising a first end portionand a second main surface on an opposite side to a surface opposing thefirst transparent substrate; a liquid crystal layer located between thefirst transparent substrate and the second transparent substrate andcontaining strip-shaped polymers and liquid crystal molecules; a firstlight-emitting element opposing the first end portion; and a first lightguide overlapping the first main surface and located between the firstend portion and the first light-emitting element, the first light guidecomprising a first surface opposing the first main surface and a secondsurface on an opposite side to the first surface, a height from thefirst main surface to the second surface being less than a height fromthe first main surface to the second main surface.